单项选择题 A package contains nitric acid solution and is radioactive. The radiation level at the package surface is 36 millirems per hour. How should this package be labeled? （）

单项选择题 A dangerous cargo manifest is needed for you to carry a combustible cargo. You should obtain the shipping papers to make this manifest from the（）.

单项选择题 A continuous sounding of a fog-signal apparatus indicates（）.